Inhibiting fogging action during color development



United States Patent Int. Cl. G03c7/16, 1/34 US. Cl. 96-22 6 ClaimsABSTRACT OF THE DISCLOSURE A silver halide photographic emulsion layeradapted to be color developed with a p-phenylenediamine derivative,comprising a colored coupler represented by the general formula (I)wherein R represents a member selected from the group consisting of analkyl group, an acylamino group, an N-arylamino group and a sulfonamidogroup; R represents a member selected from the group consisting of aphenyl group, an alkyl-substituted phenyl group, anacylamino-substituted phenyl group, an alkoxy-substituted phenyl group,a sulfo-substituted phenyl group, a naphthyl group, an alkyl-substitutednaphthyl group, an acylaminosubstituted naphthyl group, analkoxy-substituted naphthyl group, a sulfo-substituted naphthyl groupand a pyrazolyl group; and X X and X each represent a member selectedfrom the group consisting of a hydrogen atom, an alkyl group, a halogenatom, an acylamino group, an alkylcarbamoyl group, a sulfonamido group,an alkoxy group, an aryloxy group, a sulfonic acid group, an alkalimetal salt of said sulfonic acid group, an ammonium salt of saidsulfonic acid group, a carboxyl group, an alkali metal salt of saidcarboxyl group and an ammonium salt of said carboxyl group, and acolorless coupler represented by the general formula (II) wherein R Xand X have the same significance as in the above mentioned formula (I)and X, represents a member selected from the group consisting of asulfonic acid group, an alkali metal salt of said sulfonic acid group,an ammonium salt of said sulfonic acid group, a carboxyl group, analkali metal salt of said carboxyl group and an ammonium salt of saidcarboxyl group.

The present invention relates to a process for inhibiting a foggingaction during color development and more particularly to a process forpreventing color fogging in developing a silver halide photographicemulsion conice taining a coupler having --N=NR group (wherein Rrepresents a substituted or unsubstittued aryl group or heterocyclicresidual group) into the 4th position of pyrazolone or a pyrazolonederivative using a p-phenylenediamine derivative as a color developingagent.

It has been well known that the distortion of color reproduction in acolor negative-positive process by subtractive color process is causedby undesirable spectral absorption characteristics of dyes formed by thecolor development. As a process for compensating for such undesirableabsorption characteristics of the dyes, masking has been generallyadopted and for this purpose the use of a yellow-colored couplerprepared by introducing the N=NR group (wherein R is a substituted orunsubstituted aryl group or heterocyclic. residual group) into the 4thposition of pyrazolone derivative wa disclosed by US. Patent 2,455,170.When a photographic sensitive layer prepared by adding such a coupler ina silver halide photographic emulsion is exposed and colordeveloped witha p-phenylenediamine derivative, a magenta dye is formed from thecoupler at the exposed portions as a negative image while the remainingcoupler forms at the unexposed portions a yellow positive image.

When the exposed silver halide is developed using a p-phenylenediaminederivative as the color developing agent, the oxidation product of it iscoupled with these couplers in 4-position of them and also the azo groupis liberated at the same time. However, the use of the colored couplerin this case is accompanied with the following two difliculties. Thefirst point is that since the extinction coefiicient of the coloredcoupler having the N=NR group (where R is a substituted or unsubstitutedaryl group or heterocyclic residual group) is too high, the maskingeffect is liable to become excessive. Hence, it is necessary to controlmasking and as the methods, for example, the following two methods areknown. One of them is shown by US. Patent 2,428,054 in which the coloredcoupler is incorporated in one emulsion layer together with a colorlesscoupler. The other is disclosed by US. Patent 2,688,539 in which twoemulsion layers having the same color sensitivity are formed, one ofthem being incorporated with the colored coupler and another beingincorporated with a colorless coupler.

The 2nd problem is that when a silver halide photographic emulsion layercontaining a colored coupler in which the hydrogen of the activemethylene group has been substituted with an azo group is developedusing a p-phenylenediamine derivative as color developing agent, aremarkable fogging action occurs as the development proceeds. In spiteof the fact that the prevention of the formation of such fogging is veryimportant, almost no methods have been known about the preventionthereof. The formation of fogging by such an azo-substituted coloredcoupler occurs only when the p-phenylenediamine derivative is used asthe color developing agent but no fogged silver image is formed when thesame emulsion layer is processed with a developing agent for black andwhite photographic materials, such as, Metol or hydroquinone. However,when a silver halide photographic emulsion layer is processed with ap-phenylenediamine derivative as the developing agent under the presenceof a diazonium compound, remarkable fogging is observed. From thesefacts it can be considered that the formation of fogging at colordevelopment of a colored coupler with a p-phenylenediamine derivative ismarkedly increased by the liberated diazonium compound by-produced whenthe oxidation product of the color developing agent formed by foggingpeculiar to the silver halide emulsion at unexposed portions is coupledwith a colored coupler. The formation of such a kind of fogging canscarcely be prevented! by conventional fog inhibitors or stabilizers forsilver halide photographic emulsions.

The present invention is concerned with an improved process forpreventing the formation of fogging at color development with ap-phenylenediamine derivative which comprises incorporating as acolorless coupler, a pyrazolone derivative substituted at the 1stposition by a phenyl group having a carboxyl group or a sulfonic acidgroup, or an alkali metal salt or an ammonium salt of them in a silverhalide photographic emulsion layer containing as a colored coupler, apyrazolone or a derivative thereof in which the 4th position isubstituted with N=NR group (where R represents a substituted orunsubstituted aryl group or a heterocyclic residual group).

That is, in accordance with the process of this invention, the formationof fogging at development with a p-phenylenediamine derivative as thecolor developing agent is prevented effectively by incorporating in asilver halide photographic emulsion layer contaiinng as a coloredcoupler a compound shown by the following general formula (wherein Rrepresents an alkyl group, a substituted alkyl group, an acylaminogroup, an N-arylamino group, an N-substituted arylamino group, or asulfonamido group; R represents a phenyl group, a substituted phenylgroup, a naphthyl group, a substituted naphthyl group, or a heterocyclicresidual group; and X X and X each represents a hydrogen atom, an alkylgroup, a halogen atom, a substituted alkyl group, acylamino group, analkylcarbamoyl group, a substituted alkylcarbamoyl group, a sulfoamidegroup, an alkoxy group, an aryloxy group, a sulfonic acid group, or acarboxyl group), or an alkali metal salt or an ammonium salt of thecompound, and containing as a colorless coupler, a compound having thegeneral formula (wherein R X and X have the same significance as in theabove-mentioned formula (I) and X; represents a sulfonic acid group or acarboxyl group) or an alkali metal salt or an ammonia salt thereof.

Further, in the process of this invention, a colorless coupler havingthe following general formula X (III) wherein R; has the samesignificance as in the abovementioned formula (I), and X X and X eachrepreseats a hydrogen atom, a halogen atom, an alkyl group, asubstituted alkyl group, an acylamino group, an alkylcarbamoyl group, asubstituted alkylcarbamoyl group, a sulfoamide group, an alkoxy group oran aryloxy group may be used as a masking controlling agent incombination with the above-mentioned colored coupler of general formula(I) and the colorless coupler of the general formula (II) foranti-fogging.

The main structural feature of the coupler (II) for anti-fogging is thatthe 1st position of the pyrazolone is substituted with a phenyl nucleushaving the directly substituted water-solubilizable group X The couplingrate of the colorless coupler shown by the general formula (II) with theoxidation product of a p-phenyleuediamine derivative is very much higherthan that of the coupler (I) or coupler (III). Therefore, in the casewhere the three couplers (I), (II), and (III) are present together, thecoupler of the type of formula (II) can be coupled with the oxidationproduct of the p-phenylenediamine derivative more predominantly than thecouplers (I) and (III). Further, since the coupling rate of the coloredcoupler (I) with the oxidation product is almost the same as that of thecolorless coupler (III), masking can be controlled suitably.

The colorless coupler (II) cannot be used for controlling masking sincein this case coupling of the colorless coupler (II) occurspredominantly, which cannot control the masking or gives partial maskingonly. However, there occurs no fog formation by the colored coupler (I).When a small amount of the colorless coupler (II) is added with thecolored coupler (I) or a small amount of the colorless coupler (II) isadded with the colored coupler (I) and a suitable amount of thecolorless coupler (III), the small amount of the colorless coupler (II)is first consumed by color development and then coupling of the couplers(I) and (III) occurs. Therefore, if the coupler (II) is added in asuitable amount necessary for preventing color fogging that isdetermined by the silver halide emulsion to be used and the developingconditions to be adopted, the fog formation can be prevented withoutgiving substantially any effect on masking. The suitable amount of thecolorless coupler (II) for anti-fogging is about 4-50% by weight basedon the amount of the colored coupler (I).

The colored couplers (I) can be prepared by the same methods describedin US. Patents 2,455,170, 2,983,608 and 3,005,712.

The typical examples of the colored coupler (I) that can be generallyused in this invention are as follows:

The typical examples of the colorless coupler (II) for C-OH anti-foggingthat can be generally used in this invention are as follows;

CHzOOOH I and COOH

(III-1) (III-2) (III-3) HaaCw-CHC ONE I NHC O CHI-01 E CHa-COOH OHz-COOHI TABLE 4 Color fog Colorless Colorless density coupler coupler min.(III) dev.)

None III-7 0. 28 11-1 III-7 0. 12 11-2 III-7 0.09

As shown the above examples, by carrying out the color development of asilver halide photographic emulsion layer containing colored coupler (I)while incorporating in the emulsion layer colorless coupler (II), theformation of color fog can be remarkably prevented.

What is claimed is:

1. A silver halide photographic emulsion layer adapted to be colordeveloped with a p-phenylenediamine derivative, comprising a coloredcoupler represented by the general formula (I) wherein R represents amember selected from the group consisting of an alkyl group, anacylamino group, an N- arylamino group and a sulfonamido group; Rrepresents a member selected from the group consisting of a phenylgroup, an alkyl-substituted phenyl group, an acylaminosubstituted phenylgroup, an alkoxy-substituted phenyl group, a sulfo-substituted phenylgroup, a naphthyl group, an alkyl-substituted naphtyl group, anacylamino-substituted naphthyl group, an alkoxy-substituted naphthylgroup, a sulfo-substituted naphthyl group and a alkylsubstitutedpyrazolyl group; and X X and X each represents a member selected fromthe group consisting of a hydrogen atom, an alkyl group, a halogen atom,an acylamino group, an alkylcarbamoyl group, a sulfonamido group, analkoxy group, an aryloxy group, a sulfonic acid group, an alkali metalsalt of said sulfonic acid group, an ammonium salt of said sulfonic acidgroup, a carboxyl group, an alkali metal salt of said carboxyl group andan ammonium salt of said carboxyl group, and a colorless couplerrepresented by the general formula Ry-CCH:

wherein R X and X have the same significance as in the above mentionedformula (I) and X, represents a member selected from the groupconsisting of a sulfonic acid group, an alkali metal salt of saidsulfonic acid group, an ammonium salt of said sulfonic acid group, acarboxyl group, an alkali metal salt of said carboxyl group and anammonium salt of said carboxyl group.

2. The emulsion layer according to claim 1 wherein the amount of saidcolorless coupler is about 450% by weight of the amount of said coloredcoupler.

3. The emulsion according to claim 1 wherein silver halide photographicemulsion further contains a colorless coupler for masking controlrepresented by the general formula ('III) wherein R has the samesignificance as in the formula (I) shown in claim 6 and X X and X eachrepresents a member selected from the group consisting of a hydrogenatom, a halogen atom, an alkyl group, an acylamino group, analkylcarbamoyl group, a sulfonamido group, an alkoxy group, and anaryloxy group.

4. The emulsion layer according to claim 1 wherein the colored couplerof the formula (I) is a compound selected from the group consisting of:

mooou N II II CHzCOOH N\ COH SO H SOQH

and

6. The emulsion layer according to claim 3 wherein the colorless couplerof the formula (III) is a compound selected from the group consistingof:

NHCO CH-CnHu Hrs-COOH and ooNH-ocrn N o=o HHOIQCHCONH one-coon I I OCH3NORMAN G. TORCHIN, Primary Examiner ALFONSO T. SURO PICO, AssistantExaminer US. Cl. X.R.

